Improve reading QR and PDF417 code with AVFoundation swift - swift

Question

I'm trying to read PDF-417 and QR code and my code works but when there is less light or blurred image does not work. So I am looking for information about how may improve reading code.
I tried changing the settings on the camera: AVCaptureSession Increased the resolution settings and the AVCaptureDevice Increased videoZoomFactor but apparently I'm not doing it correctly.
I hope you can help me.
import UIKit
import AVFoundation
class ViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
let session : AVCaptureSession = AVCaptureSession()
var previewLayer : AVCaptureVideoPreviewLayer!
var highlightView : UIView = UIView()
override func viewDidLoad() {
super.viewDidLoad()
/
self.highlightView.autoresizingMask = UIViewAutoresizing.FlexibleTopMargin |
UIViewAutoresizing.FlexibleBottomMargin |
UIViewAutoresizing.FlexibleLeftMargin |
UIViewAutoresizing.FlexibleRightMargin
/
self.highlightView.layer.borderColor = UIColor.greenColor().CGColor
self.highlightView.layer.borderWidth = 3
/
self.view.addSubview(self.highlightView)
/
let device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
/
/
var error : NSError? = nil
let input : AVCaptureDeviceInput? = AVCaptureDeviceInput.deviceInputWithDevice(device, error: &error) as? AVCaptureDeviceInput
/
if input != nil {
session.addInput(input)
}
else {
/
println(error)
}
let output = AVCaptureMetadataOutput()
output.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue())
session.addOutput(output)
output.metadataObjectTypes = output.availableMetadataObjectTypes
previewLayer = AVCaptureVideoPreviewLayer.layerWithSession(session) as! AVCaptureVideoPreviewLayer
previewLayer.frame = self.view.bounds
previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
self.view.layer.addSublayer(previewLayer)
/
session.startRunning()
}
/
func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!) {
var highlightViewRect = CGRectZero
var barCodeObject : AVMetadataMachineReadableCodeObject!
var detectionString : String!
let barCodeTypes = [
AVMetadataObjectTypePDF417Code,
AVMetadataObjectTypeQRCode
]
/
for metadata in metadataObjects {
for barcodeType in barCodeTypes {
if metadata.type == barcodeType
{
barCodeObject = self.previewLayer.transformedMetadataObjectForMetadataObject(metadata as! AVMetadataMachineReadableCodeObject) as! AVMetadataMachineReadableCodeObject
highlightViewRect = barCodeObject.bounds
detectionString = (metadata as! AVMetadataMachineReadableCodeObject).stringValue
self.session.stopRunning()
self.alert(detectionString)
break
}
}
}
println(detectionString)
self.highlightView.frame = highlightViewRect
self.view.bringSubviewToFront(self.highlightView)
}
func alert(Code: String)
{
let actionSheet:UIAlertController = UIAlertController(title: "Barcode", message: "\(Code)", preferredStyle: UIAlertControllerStyle.Alert)
let firstAlertAction:UIAlertAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler:
{
(alertAction:UIAlertAction!) in
self.session.startRunning()
})
actionSheet.addAction(firstAlertAction)
self.presentViewController(actionSheet, animated: true, completion: nil)
}
}

Answer 1

I struggled with unconsistent reading of qr-codes, what worked for me was to get the qr-code as proportional as possible. (If reading from another iphone/ipad screen) If that doesnt help you, the http://www.appcoda.com/qr-code-reader-swift/ <-- helped me out
cheers